AbstractsChemistry

On the microscopic determination of cadmium in metallic zinc

by J. P. (James Presley) Gill




Institution: Missouri University of Science and Technology
Department:
Year: 1919
Record ID: 1566437
Full text PDF: http://hdl.handle.net/10355/35752


Abstract

"A quick and accurate determination of Cadmium in Metallic Zinc by all ordinary chemical methods now in use, so far as the writer has been able to ascertain is at best only approximate. However, longer methods and very delicate ones for determining Cadmium are in use that are very accurate, but these methods are so long and so delicate that very few commercial laboratories care to use them. Now, it has been known for some time that Zinc and Cadmium do not form an alloy which when in the solid exist either as a solution or a compound. They do form a eutectic mixture at about 84 per cent Cadmium and 16 per cent Zinc, but this eutectic mixture will separate from both the metallic Cadmium and the metallic Zinc by fractional crystallization. Thus with zinc ingots or bars it has been noticed that when they were high in Cadmium a reddish black substance seemed to separate during freezing and come to the top of the bar or ingot. Therefore, many time the Zinc bars or ingots that were high in Cadmium could be identified before running a chemical analysis on them. This gave rise to the question "why couldn't Cadmium in Zinc be determined microscopically in some such manner as oxygen is determined in Copper?" Thus the reason for this thesis" – Introduction, Page 1.